A scientist recruited by the renowned Cleveland Clinic is stuck in India because his visa is delayed. An entrepreneur courted by Silicon Valley companies had his application denied. Many green card applicants have new interviews to pass.

Immigration and State Department officials are more closely scrutinizing, and have started more frequently denying, visas for people seeking to visit the United States on business, as well as for those recruited by American companies, according to lawyers representing visa seekers. Foreigners already in the United States whose employers wish to extend their stay also are facing new hurdles.